Composition for enamel, method for preparing a composition for enamel, and cooking appliance

ABSTRACT

A composition for enamel may include 20 to 45 wt % of SiO2; 1 to 15 wt % of B2O3, 10 to 20 wt % of one or more of Na2O, K2O, and Li2O, 1 to 5 wt % of NaF, 1 to 10 wt % of ZnO, 5 to 15 wt % of TiO2, 3 to 7 wt % of MoO3; 5 to 15 wt % of Bi2O3, 1 to 5 wt % of CeO2, and 1 to 10 wt % of one or more of MnO2, Fe2O3, and Co3O4. The composition may be used to coat a cooking appliance for easy removal of contaminants at room temperature.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present disclosure claims priority to and the benefit of KoreanPatent Application No. 10-2019-0164055, filed in Korea on Dec. 10, 2019,the disclosure of which is incorporated herein by reference in itsentirety.

BACKGROUND 1. Field

The present disclosure relates to a composition for enamel.

2. Background

Enamel may be a glassy glaze covering a surface of a metal plate.General enamel is used for cooking appliances such as a microwave or anoven. Cooking appliances such as an electric oven, a gas oven, etc. maycook food by using a heat source. Contaminants, etc. that occur in acooking process may adhere to an inner wall of a cavity of the cookingappliance, and the inner wall of the cavity may need to be cleaned. Theenamel may be coated on a surface of the inner wall of the cavity of thecooking appliance to ease removal of any contaminants fixed to thecooking appliance. In general, a pyrolysis method may be used to cleanthe inner wall of the cavity by reducing the contaminants to ashes bycombusting the contaminants at a high temperature. A composition forenamel used in the pyrolysis method may include constituents of P₂O₅,SiO₂, B₂O₃, etc., which may be cleaned by heating for about 4 hours at450° C. to 500° C. For example, U.S. Pat. No. 3,547,098 discloses aporcelain enamel for a self-cleaning oven.

Due to such a high temperature, the existing compositions for enamel mayrequire a large amount of energy during cleaning. Also, the enamel maynot otherwise be easily cleaned if the enamel is not processed by heattreatment at a high temperature. Therefore, an application of such anenamel may be limited to the inner surface of the cooking appliance andmay not be beneficial at an outer surface of the cooking appliance. Inaddition, such an enamel may require a soaking process using water for apredetermined time so as to remove oil-based contaminants coming fromcooking pork, beef, and poultry, further complicating a cleaningprocess.

The above references are incorporated by reference herein whereappropriate for appropriate teachings of additional or alternativedetails, features and/or technical background.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the followingdrawings in which like reference numerals refer to like elements, andwherein:

FIG. 1 is a front view showing a cooking appliance according to anexample of the present disclosure; and

FIG. 2 is a photo related to adhesion evaluation criteria of an exampleand a comparative example.

DETAILED DESCRIPTION

Hereinafter, a composition for enamel according to some examples of thepresent disclosure, a method for preparation thereof, and a cookingappliance are described.

<Composition for Enamel>

A composition for enamel according to the present disclosure may include20 to 45 weight percent (wt %) of silicon dioxide (SiO₂); 1 to 15 wt %of boron trioxide or diboron trioxide (B₂O₃); 10 to 20 wt % of one ormore of sodium oxide (Na₂O), potassium oxide (K₂O), and/or lithium oxide(Li₂O); 1 to 5 wt % of sodium fluoride (NaF); 1 to 10 wt % of zinc oxide(ZnO); 5 to 15 wt % of titanium dioxide (TiO₂); 3 to 7 wt % ofmolybdenum trioxide or molybdenum(IV) oxide (MoO₃); 5 to 15 wt % ofbismuth oxide or bismuth(III) oxide Bi₂O₃; 1 to 5 wt % of cerium dioxideor cerium(IV) oxide (CeO₂); and 1 to 10 wt % of one or more of manganesedioxide or manganese(IV) oxide (MnO₂), ferric oxide or iron(III) oxide(Fe₂O₃), and/or cobalt oxide or cobalt(II, IIII) oxide (Co₃O₄). A totalcontent of Na₂O, K₂O, and Li₂O may be 10 to 20 wt %. A total content ofMnO₂, Fe₂O₃, and Co₃O₄ may be 1 to 10 wt %.

SiO₂ may be a constituent forming a glass structure that strengthens aframe of the glass structure so that chemical resistance of thecomposition for enamel may be enhanced, and expression ofcharacteristics of a metal oxide acting as a catalyst may be eased. Acatalytic metal oxide may be inferior in respect of thermal resistanceor chemical resistance compared to other constituents, and the catalyticmetal oxide may not be contained in a large amount. However, if acertain amount of SiO₂ is contained in a glass composition, solubilityof the catalytic metal oxide may be enhanced within the glass becauseSiO₂ has a structure having a large a pore size. A content ratio of SiO₂and the catalytic metal oxide may be controlled or predetermined so thatexcellent thermal resistance and chemical resistance may be obtained,and characteristics of the catalytic metal oxide may be expressed. SiO₂may be included in the composition for enamel in a range of 20 to 45 wt%. If SiO₂ exceeds 45 wt %, addition of other constituents may beinterfered with, which may inhibit or reduce cleaning functions orproperties. If SiO₂ is less than 20 wt %, a silicate-based glasscomposition according to the present disclosure may collapse.

B₂O₃ may help form a glass composition and may help with uniformity in amelting process of each of the constituents of the glass composition.Also, B₂O₃ may help to control a coefficient of thermal expansion and afusion flow of the glass composition, enhancing coating performance.B₂O₃ may help maintain proper viscosity upon a calcination process ofenamel and so that crystallization of the glass composition may notoccur or be less likely to occur. B₂O₃ may be contained in the glasscomposition in a range of 1 to 15 wt %. If B₂O₃ exceeds 15 wt %,addition of other constituents may be interfered with, which may inhibitor reduce performance or cleaning functions, properties, orcapabilities. If B₂O₃ is less than 1 wt %, the glass composition maycollapse or crystallize.

Li₂O, Na₂O, and K₂O may enhance cleaning capabilities of the enamelcomposition. One or more of Li₂O, Na₂O, and/or K₂O may be contained in arange of 10 to 20 wt % in the enamel composition. If one or more ofLi₂O, Na₂O, and/or K₂O exceeds 20 wt %, a coefficient of thermalexpansion of glass may greatly increase and coating performance may belowered. If a content of one or more of Li₂O, Na₂O, and K₂O is 10 wt %or less, cleaning capabilities may be reduced. The composition forenamel according to the present disclosure may include 5 wt % or more ofNa₂O.

NaF may also enhance the cleaning function of the enamel composition.NaF may be contained in a range of 1 to 5 wt % in the composition forenamel. If a content of NaF exceeds 5 wt %, addition of otherconstituents may be interfered with, which may reduce durability. If acontent of NaF is 1 wt % or less, cleaning capabilities may be reduced.

ZnO may be an intermediate oxide to balance a network formation oxide(SiO₂ and B₂O₃) and an alkali oxide (Li₂O, Na₂O, and K₂O). In thepresent disclosure, ZnO may be contained in a range of 1 to 10 wt % inthe composition for enamel. If a content of Zno exceeds 10 wt %,addition of other constituents may be interfered with, which may lowerdurability or cleaning capabilities. If a content of ZnO is 1 wt % orless, the cleaning capabilities may be reduced. TiO₂, MoO₃, Bi₂O₃, andCeO₂ may enhance cleaning performance with respect to contaminants suchas oil-based contaminants or saccharides and may improve adhesionperformance of the composition for enamel when coated on a substrate.

In the present disclosure, 5 to 15 wt % of TiO₂, 3 to 7 wt % of MoO₃, 5to 15 wt % of Bi₂O₃, and 1 to 5 wt % of CeO₂ may be included. If thecomposition for enamel includes a minimum constituent content or less ofthe above constituents, cleaning performance with respect tocontaminants such as oil-based contaminants and saccharides may beweakened and adhesion performance to the substrate may be lowered. Onthe contrary, if the composition for enamel of the present disclosureincludes more than a maximum constituent content of the aboveconstituents, addition of other constituents may be interfered with, anddurability or chemical resistance may be lowered.

In addition, the composition for enamel may include 1 to 10 wt % of oneor more of MnO₂, Fe₂O₃, and/or Co₃O₄ to further enhance adhesionperformance to a substrate of a steel plate. If one or more of MnO₂,Fe₂O₃, and/or Co₃O₄ is 1 wt % or less, adhesion performance between anenamel coating and the substrate of the steel plate may be weakened. Onthe contrary, if one or more of MnO₂, Fe₂O₃, and/or Co₃O₄ exceeds 10 wt%, addition of other constituents may be interfered with and cleaningperformance may be weakened.

TiO₂, MoO₃, MnO₂, and/or Fe₂O₃ may enhance cleaning performance withrespect to oil-based contaminants. If TiO₂ and MoO₃ are concurrentlyapplied to a silicate-based composition, such as the composition forenamel of the present disclosure, contaminants may be filmized or form afilm due to catalytic activity of TiO₂ and MoO₃. As previouslydescribed, the composition for enamel of the present disclosure mayinclude 5 to 15 wt % of TiO₂ and 3 to 7 wt % of MoO₃.

Bi₂O₃, CeO₂, and Co₃O₄ may enhance cleaning performance with respect tosaccharide contaminants. If a large amount of Bi₂O₃ is applied to asilicate-based composition, such as the composition for enamel of thepresent disclosure, saccharide contaminants may be easily removed by awet sponge even at a room temperature due to catalytic activity of Bi₂O₃to saccharide contaminants. Balance of all constituents is important tomaximize cleaning performance of the enamel coating.

Next, as previously described, Co₃O₄, Fe₂O₃, and MnO₂ may enhanceadhesion of the enamel coating. Also, Co₃O₄, Fe₂O₃, and MnO₂ may beapplied as a color realization element of the enamel coating.

The composition for enamel may include catalytic oxide constituents(TiO₂, MoO₃, Bi₂O₃, CeO₂, and one or more of MnO₂, Fe₂O₃, and/or Co₃O₄)in which a total content thereof is 40 wt % or less. If the catalyticoxides exceed 40 wt %, durability and chemical resistance of the enamelcoating may be lowered. A total content of the catalytic oxides may becontrolled accordingly in the composition for enamel of the presentdisclosure.

The composition for enamel according to the present disclosure may havea composition ratio in which constituents for realizing glass andconstituents having catalytic performance are optimized. Cleaning may bepossible with respect to all contaminants without soaking in water at aroom temperature.

<Method of Preparing a Composition for Enamel>

A method of preparing the composition for enamel according to thepresent disclosure may include steps of providing a material of thecomposition for the enamel containing all constituents as noted above,melting the material of the composition for the enamel, and quenching amelted material of the composition, thereby forming the composition forthe enamel.

The material of the composition for enamel may be sufficiently mixed,and then the material of the composition for enamel may be melted. Thematerial of the composition may be melted in a temperature range of1,200 to 1,500° C. for 1 to 2 hours. The melted material of thecomposition may be quenched using a chiller, etc., and/or a quenchingroller. Accordingly, the composition for enamel may be prepared.

<Cooking Appliance>

The finalized composition for enamel may be coated on a surface of atarget object (e.g., a part of a metal plate, a glass plate, and/or acooking appliance). The composition may be coated on an outer surface ofa cooking appliance where heat treatment may not be possible.

Referring to FIG. 1 , a cooking appliance 1 according to the presentdisclosure may include a cavity 11 in which a cooking space 12 isformed, a door 14 to selectively open and/or close the cooking space 12,at least one heat source 13, 15, and/or 16 providing heat to heat orcook food in the cooking space 12, and a coating layer 17 coated on aninner surface of the cavity 11 and/or an inner surface of the door 14and formed by the composition for enamel according to the presentdisclosure.

The cavity 11 may have a hexahedron shape having at least one openedface or surface. The heat source 13, 15, 16 may include a convectionassembly 13 that allows heated air to be discharged inside the cavity11, an upper heater 15 provided at an upper part or side of the cavity11, and a lower heater 16 provided at a lower part or side of the cavity11. The upper heater 15 and the lower heater 16 may be equipped insideor outside the cavity 11. The heat sources 13, 15, and/or 16 may notnecessarily include the convection assembly 13, the upper heater 15, andthe lower heater 16. The heat source 13, 15, 16 may include any one ormore of the convection assembly 13, the upper heater 15, and the lowerheater 16, or alternatively may include different heaters. Embodimentsdisclosed herein are not limited.

The composition for enamel according to the present disclosure may becoated on an inner surface of the cavity 11 of the cooking appliance 1,an inner surface of the door 14, or an inner surface of a door glass 14′by a dry process or a wet process to form the coating layer 17. Thecavity 11 and the door 14 may be formed as a metal plate. The coatinglayer 17 using the composition for enamel according to the presentdisclosure may be directly coated on the metal plate as a single layer.

Also, the composition for enamel according to the present disclosure maybe applied to the cooking appliance including a glass plate and at leastone heat source provided below the glass plate. The coating layer 17that is formed by the glass composition according to the presentdisclosure may be provided at an upper portion of the glass plate.

Hereinafter, a specific embodiment of the present disclosure is examinedbased on an example.

Example

<Preparation of Glass Composition>

The glass composition having a composition ratio described in Table 1below was prepared. A raw material of each constituent was sufficientlymixed in a V-mixer for 3 hours. Here, Na₂CO₃, K₂CO₃, and Li₂CO₃ wereused as raw materials of Na₂O, K₂O, and Li₂O, respectively. With respectto the other constituents, the same constituent as that described inTable 1 was used. A mixed material was sufficiently melted at 1,300° C.for 1 hour and 30 minutes and was quenched in a quenching roller,thereby yielding a glass cullet.

0.1 wt % to 1 wt % of organopolysiloxane (DOW Corning 1107) was mixedwith the glass cullet yielded by the above process. A mixture thereofwas ground for about 5 hours using a ball mill and then was passedthrough a 325 mesh sheave (ASTM C285-88). Powder that passed through themesh sheave was used as a frit of the composition for enamel.

TABLE 1 Constituent Example Comparative example (wt %) 1 2 3 1 2 3 SiO₂38.11 40.70 37.30 38.30 42.00 36.00 B₂O₃ 9.02 8.39 10.30 13.11 7.3210.32 Na₂O 10.96 12.46 12.34 10.75 14.00 10.11 K₂O 2.08 1.12 2.11 6.526.13 6.13 Li₂O 1.00 0 0 2.54 2.39 2.39 NaF 1.63 2.74 2.71 3.62 3.41 3.41TiO₂ 11.14 11.60 9.50 14.17 19.00 13.32 MnO₂ 0 0.69 0.68 0 0 0 Fe₂O₃0.56 0 0.99 0 0 0 Co₃O₄ 1.93 1.90 2.88 0 0 0 ZnO 8.51 4.70 4.65 10.984.00 10.32 MoO₃ 4.81 5.01 4.96 0 1.75 3.83 Bi₂O₃ 8.93 9.31 10.20 0 02.83 CeO₂ 1.32 1.38 1.36 0 0 1.33

Based on the values of Table 1, materials for the composition mayinclude SiO₂ provided in a range of 36 to 42 wt %, B₂O₃ provided in arange of 7 to 12 wt %, Na₂O provided in a range of 9 to 14 wt %, K₂Oprovided in a range of 0 to 3 wt %, Li₂O provided in a range of 0 to 2wt %, NaF provided in a range of 1 to 3 wt %, ZnO provided in a range of3 to 10 wt %, TiO₂ provided in a range of 8 to 13 wt %, MoO₃ provided ina range of 4 to 6 wt %, Bi₂O₃ provided in a range of 7 to 12 wt %, CeO₂provided in a range of 1 to 3 wt %, MnO₂ provided in a range of 0 to 2wt %, Fe₂O₃ provided in a range of 0 to 2 wt %, and/or Co₃O₄ provided ina range of 0 to 3 wt %.

Based on the values of Table 1, materials for the composition mayinclude SiO₂ provided in a range of 37 to 41 wt %, B₂O₃ provided in arange of 8 to 11 wt %, Na₂O provided in a range of 6 to 13 wt %, K₂Oprovided in a range of 0 to 2.5 wt %, Li₂O provided in a range of 0 to1.5 wt %, NaF provided in a range of 1.4 to 2.9 wt %, ZnO provided in arange of 4 to 9 wt %, TiO₂ provided in a range of 9 to 12 wt %, MoO₃provided in a range of 4.5 to 5.5 wt %, Bi₂O₃ provided in a range of 8to 11 wt %, CeO₂ provided in a range of 1 to 2 wt %, MnO₂ provided in arange of 0 to 1 wt %, Fe₂O₃ provided in a range of 0 to 1.5 wt %, and/orCo₃O₄ provided in a range of 1 to 3 wt %.

Based on the values in Table 1, materials for the composition mayinclude SiO₂ provided in a range of 37.2 to 40.8 wt %, B₂O₃ provided ina range of 8.3 to 10.5 wt %, Na₂O provided in a range of 10.5 to 12.6 wt%, K₂O provided in a range of 1.1 to 2.2 wt %, Li₂O provided in a rangeof 0 to 1.1 wt %, NaF provided in a range of 1.5 to 2.8 wt %, ZnOprovided in a range of 4.5 to 8.8 wt %, TiO₂ provided in a range of 9.3to 11.7 wt %, MoO₃ provided in a range of 4.7 to 5.1 wt %, Bi₂O₃provided in a range of 8.5 to 10.5 wt %, CeO₂ provided in a range of 1.2to 1.5 wt %, MnO₂ provided in a range of 0 to 0.8 wt %, Fe₂O₃ providedin a range of 0 to 1.2 wt %, or Co₃O₄ provided in a range of 1.8 to 3 wt%. SiO₂ provided in a range of 37.30 to 40.70 wt %, B₂O₃ provided in arange of 8.39 to 10.30 wt %, Na₂O provided in a range of 10.96 to 12.46wt %, K₂O provided in a range of 1.12 to 2.11 wt %, Li₂O provided in arange of 0 to 1.00 wt %, NaF provided in a range of 1.63 to 2.74 wt %,ZnO provided in a range of 4.65 to 8.51 wt %, TiO₂ provided in a rangeof 9.50 to 11.60 wt %, MoO₃ provided in a range of 4.81 to 5.01 wt %,Bi₂O₃ provided in a range of 8.93 to 10.20 wt %, CeO₂ provided in arange of 1.32 to 1.38 wt %, MnO₂ provided in a range of 0 to 0.69 wt %,Fe₂O₃ provided in a range of 0 to 0.99 wt %, or Co₃O₄ provided in arange of 1.90 to 2.88 wt %.

Based on the values in Table 1, a total content of Na₂O, K₂O, and Li₂Omay be provided in a range of 12 to 16 wt %. A total content of MnO₂,Fe₂O₃, and Co₃O₄ provided in a range of 1 to 5 wt %. A total content ofNa₂O, K₂O, and Li₂O may be provided in a range of 13.5 to 15.0%. A totalcontent of MnO₂, Fe₂O₃, and Co₃O₄ may be provided in a range of 2.4 to4.6 wt %.

<Preparation of Sample of Composition for Enamel>

The frit for enamel prepared as the above was sprayed on a low carbonsteel sheet that has 200×200 (mm) and 1 (mm) or less of thickness usinga general corona discharge gun. A voltage of the corona discharge gunwas controlled in a range of 40 kV to 100 kV. An amount of the fritsprayed on the low carbon steel sheet was about 300 g/m². The low carbonsteel sheet on which the frit for enamel as the above was sprayed wascalcinated for 300 to 450 seconds in a temperature range of 780° C. to850° C.

Experimental Example 1—Evaluation for Cleaning Performance

With respect to the samples according to the example and the comparativeexample, cleaning performance was evaluated as below.

A method for measuring cleaning performance is as follows. About 1 g ofchickens' oil as a contaminant was evenly and thinly spread with a brushon a surface of the samples according to the example and the comparativeexample. Next, test samples on which the contaminant was spread was putinto a thermostat so that the contaminant was fixed thereto in atemperature condition of 270° C. and a time condition of 30 minutes.After fixation, the test samples were naturally cooled. Then, thechickens' oil was wiped by 3 kgf or less of a force using a fryingpan-only sponge that was wet with cold water. A part wiped from asurface of the contaminated enamel was uniformized by using a bar havinga flat bottom and a diameter is 5 cm. Here, the number of wiping swipesor reciprocations is measured, wherein the number is defined as thenumber of cleaning reciprocations. An index of evaluation is describedas a table in a left side below. Also, in the case that the contaminantis tomato sources, the cleaning performance was evaluated in the samemethod as the above.

TABLE 2 The number of cleaning reciprocations Level  ~5 5 ~15 4 ~25 3~50 2   50~ 1

Experimental Example 2—Evaluation of Adhesion Performance

Adhesion of the example and the comparative example was measured. As amethod of measuring adhesion, Dupont Impact Tester (ASTM D1794, JISK5400) was used. Test samples were placed at a center of a sample stage,and a steel ball having about 25.4 nm (1 inch) of a diameter wasinstalled at a center of a planar portion of the test samples. Then, aniron piece having 2 kg in weight was free-fallen at 300 nm in height toexamine a state of peeling. Criteria of determining an adhesion levelare based on criteria shown in FIG. 3 .

<Test Results>

Test results of the above experimental examples were described in Table3.

TABLE 3 Comparative Comparative Comparative Example 1 Example 2 Example3 example 1 example 2 example 3 Cleaning Lv. 5 Lv. 5 Lv. 5 Lv. 2 Lv. 3Lv. 5 Performance with respect to chickens' oil Cleaning Lv. 4 Lv. 5 Lv.5 Lv. 1 Lv. 1 Lv. 2 Performance with respect to tomato sources AdhesionLv. 3 Lv. 4 Lv. 5 Lv. 0 Lv. 0 Lv. 1

As the test results, all contaminants of samples according to examples 1to 3 were easily removed at a room temperature. On the contrary, allcontaminants of comparative examples were not easily removed at a roomtemperature. In addition, the examples have excellent cleaningperformance and also excellent adhesion. However, it was confirmed thatcomparative examples do not have good adhesion.

Embodiments disclosed herein may provide a new composition for enamel inthat cleaning is possible with respect to all contaminants in a roomtemperature. Embodiments disclosed herein may provide a new compositionfor enamel in that cleaning is possible with respect to all contaminantswithout soaking in water. Embodiments disclosed herein may provide a newcomposition for enamel where cleaning is possible without soaking inwater at a room temperature and that also has excellent durability.

Objectives of the present disclosure are not limited to theabove-described ones. Additionally, other objectives and advantages thathave not been mentioned may be clearly understood from the descriptionand may be more clearly understood from embodiments of the presentdisclosure. Further, it will be understood that the objectives andadvantages of the present disclosure may be realized via means andcombinations thereof that are described in the appended claims.

In order to be cleaned with respect to all contaminants without soakingin water at a room temperature, the composition for enamel according tothe present disclosure may have a configuration of including asilicate-based component and a catalytic oxide in a new compositionratio. The composition for enamel according to the present disclosuremay include SiO₂, B₂O₃, R₂O (one or more of Na₂O, K₂O, and/or Li₂O),NaF, ZnO, TiO₂, MoO₃, Bi₂O₃, CeO₂, and one or more of MnO₂, Fe₂O₃,and/or Co₃O₄ in a new composition ratio. Also, the composition forenamel according to the present disclosure may include 40% by weight(hereinafter referred to as “wt %”) or less of TiO₂, MoO₃, Bi₂O₃, CeO₂,and one or more of MnO₂, Fe₂O₃, and/or Co₃O₄ in order to increase ormaximize chemical resistance and durability.

Based on the values of Table 1, materials for the composition mayinclude SiO₂ provided in a range of 36 to 42 wt %, B₂O₃ provided in arange of 7 to 12 wt %, Na₂O provided in a range of 9 to 14 wt %, K₂Oprovided in a range of 0 to 3 wt %, Li₂O provided in a range of 0 to 2wt %, NaF provided in a range of 1 to 3 wt %, ZnO provided in a range of3 to 10 wt %, TiO₂ provided in a range of 8 to 13 wt %, MoO₃ provided ina range of 4 to 6 wt %, Bi₂O₃ provided in a range of 7 to 12 wt %, CeO₂provided in a range of 1 to 3 wt %, MnO₂ provided in a range of 0 to 2wt %, Fe₂O₃ provided in a range of 0 to 2 wt %, and/or Co₃O₄ provided ina range of 0 to 3 wt %.

Based on the values of Table 1, materials for the composition mayinclude SiO₂ provided in a range of 37 to 41 wt %, B₂O₃ provided in arange of 8 to 11 wt %, Na₂O provided in a range of 6 to 13 wt %, K₂Oprovided in a range of 0 to 2.5 wt %, Li₂O provided in a range of 0 to1.5 wt %, NaF provided in a range of 1.4 to 2.9 wt %, ZnO provided in arange of 4 to 9 wt %, TiO₂ provided in a range of 9 to 12 wt %, MoO₃provided in a range of 4.5 to 5.5 wt %, Bi₂O₃ provided in a range of 8to 11 wt %, CeO₂ provided in a range of 1 to 2 wt %, MnO₂ provided in arange of 0 to 1 wt %, Fe₂O₃ provided in a range of 0 to 1.5 wt %, and/orCo₃O₄ provided in a range of 1 to 3 wt %.

Based on the values in Table 1, materials for the composition mayinclude SiO₂ provided in a range of 37.2 to 40.8 wt %, B₂O₃ provided ina range of 8.3 to 10.5 wt %, Na₂O provided in a range of 10.5 to 12.6 wt%, K₂O provided in a range of 1.1 to 2.2 wt %, Li₂O provided in a rangeof 0 to 1.1 wt %, NaF provided in a range of 1.5 to 2.8 wt %, ZnOprovided in a range of 4.5 to 8.8 wt %, TiO₂ provided in a range of 9.3to 11.7 wt %, MoO₃ provided in a range of 4.7 to 5.1 wt %, Bi₂O₃provided in a range of 8.5 to 10.5 wt %, CeO₂ provided in a range of 1.2to 1.5 wt %, MnO₂ provided in a range of 0 to 0.8 wt %, Fe₂O₃ providedin a range of 0 to 1.2 wt %, or Co₃O₄ provided in a range of 1.8 to 3 wt%. SiO₂ provided in a range of 37.30 to 40.70 wt %, B₂O₃ provided in arange of 8.39 to 10.30 wt %, Na₂O provided in a range of 10.96 to 12.46wt %, K₂O provided in a range of 1.12 to 2.11 wt %, Li₂O provided in arange of 0 to 1.00 wt %, NaF provided in a range of 1.63 to 2.74 wt %,ZnO provided in a range of 4.65 to 8.51 wt %, TiO₂ provided

in a range of 9.50 to 11.60 wt %, MoO₃ provided in a range of 4.81 to5.01 wt %, Bi₂O₃ provided in a range of 8.93 to 10.20 wt %, CeO₂provided in a range of 1.32 to 1.38 wt %, MnO₂ provided in a range of 0to 0.69 wt %, Fe₂O₃ provided in a range of 0 to 0.99 wt %, or Co₃O₄provided in a range of 1.90 to 2.88 wt %.

Based on the values in Table 1, a total content of Na₂O, K₂O, and Li₂Omay be provided in a range of 12 to 16 wt %. A total content of MnO₂,Fe₂O₃, and Co₃O₄ provided in a range of 1 to 5 wt %. A total content ofNa₂O, K₂O, and Li₂O may be provided in a range of 13.5 to 15.0%. A totalcontent of MnO₂, Fe₂O₃, and Co₃O₄ may be provided in a range of 2.4 to4.6 wt %.

This application is related to co-pending U.S. application Ser. No.17/117,440 filed on Dec. 10, 2020, the entire contents of which areincorporated by reference herein.

The composition for enamel according to the present disclosure may becleaned with respect to all contaminants at a room temperature. Also,the composition for enamel according to the present disclosure may becleaned with respect to all contaminants without soaking in water. Thecomposition for enamel according to the present disclosure may becleaned without soaking in water at a room temperature and also hasexcellent durability.

In addition to effects as the above, specific effects of the presentdisclosure may be described together with describing specific mattersfor implementing the present disclosure. The present disclosure has beendescribed with reference to the embodiments illustrated in the drawings.However, it is obvious that the disclosure may be changed by one havingordinary skill in the art to which the disclosure pertains in variousdifferent forms within the scope of the technical spirit of thedisclosure. Therefore, the present disclosure is not limited to theembodiments and the drawings set forth herein. Further, even thoughaction and effects according to configuration of the present disclosureare not definitely described in the description of embodiments of thepresent disclosure, it is certain that predictable effects resulted fromthe relevant configuration should be also admitted.

The pre-described objectives, features, and advantages will be describedspecifically hereinafter referring to the attached drawings; thereforethose skilled in the art may easily realize the technical sprit of thepresent disclosure. In describing the present disclosure, the detaileddescription of known technologies in relation to the present disclosurewill be omitted if it is deemed to make the gist of the presentdisclosure unnecessarily vague. Throughout the drawings, identicalreference numerals may denote identical or similar components.

When any component is described as being “at an upper portion (or alower portion)” of a component, or “on (or under)” a component, anycomponent may be placed on the upper surface (or the lower surface) ofthe component, and an additional component may be interposed between thecomponent and any component placed on (or under) the component. When acomponent is described as being “connected,” “coupled” or “linked” toanother component, the component may be directly connected or able to belinked to another component; however, it is also to be understood thatan additional component may be “interposed” between the two components,or the two components may be “connected,” “coupled” or “linked” throughan additional component.

In a whole of specification, each component may be singular or plural aslong as there is no description particularly opposite to the above. Asingular expression used in this specification includes a pluralexpression as long as the expression is not definitely differentlyindicated in the context. In the present application, the term“configure” or “include,” etc. should not be construed to necessarilyinclude all of various components or various steps described inspecification. It should be construed such that some components or somesteps of the above may not be included, or additional components orsteps may be further included.

In the whole of specification, when the term “A and/or B” is used, theterm means A, B, or A and B as long as there is no descriptionparticularly opposite to the above. When the term “C to D” is used, theterm means C or more and D or less as long as there is no descriptionparticularly opposite to the above.

It will be understood that when an element or layer is referred to asbeing “on” another element or layer, the element or layer can bedirectly on another element or layer or intervening elements or layers.In contrast, when an element is referred to as being “directly on”another element or layer, there are no intervening elements or layerspresent. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section could be termed a second element,component, region, layer or section without departing from the teachingsof the present invention.

Spatially relative terms, such as “lower”, “upper” and the like, may beused herein for ease of description to describe the relationship of oneelement or feature to another element(s) or feature(s) as illustrated inthe figures. It will be understood that the spatially relative terms areintended to encompass different orientations of the device in use oroperation, in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas “lower” relative to other elements or features would then be oriented“upper” relative to the other elements or features. Thus, the exemplaryterm “lower” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (rotated 90 degrees or at otherorientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Embodiments of the disclosure are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the disclosure.As such, variations from the shapes of the illustrations as a result,for example, of manufacturing techniques and/or tolerances, are to beexpected. Thus, embodiments of the disclosure should not be construed aslimited to the particular shapes of regions illustrated herein but areto include deviations in shapes that result, for example, frommanufacturing.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment. The appearances ofsuch phrases in various places in the specification are not necessarilyall referring to the same embodiment. Further, when a particularfeature, structure, or characteristic is described in connection withany embodiment, it is submitted that it is within the purview of oneskilled in the art to effect such feature, structure, or characteristicin connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A composition comprising: 20 to 45 weight percent(wt %) of silicon dioxide (SiO₂); 1 to 15 wt % of diboron trioxide(B₂O₃); 10 to 20 wt % of at least one of sodium oxide (Na₂O), potassiumoxide (K₂O), or lithium oxide (Li₂O); 1 to 5 wt % of sodium fluoride(NaF); 1 to 10 wt % of zinc oxide (ZnO); 5 to 15 wt % of titaniumdioxide (TiO₂); 3 to 7 wt % of molybdenum trioxide (MoO₃); 5 to 15 wt %of bismuth oxide (Bi₂O₃); 1 to 5 wt % of cerium dioxide (CeO₂); and morethan 5 to 10 wt % of at least one of manganese dioxide (MnO₂), ferricoxide (Fe₂O₃), or cobalt oxide (CO₃O₄).
 2. The composition claim 1,comprising 5 wt % or more of Na₂O.
 3. The composition of claim 1,wherein a total content of TiO₂, MoO₃, Bi₂O₃, CeO₂, and the at least oneof MnO₂, Fe₂O₃, or Co₃O₄ is 40 wt % or less.
 4. The composition of claim1, wherein: the SiO₂ is provided in a range of 36 to 42 wt %; the B₂O₃is provided in a range of 7 to 12 wt %; Na₂O is provided in a range of 9to 14 wt %; K₂O is provided in a range of 0 to 3 wt %; Li₂O is providedin a range of 0 to 2 wt %; NaF is provided in a range of 1 to 3 wt %;ZnO is provided in a range of 3 to 10 wt %; TiO₂ is provided in a rangeof 8 to 13 wt %; MoO₃ is provided in a range of 4 to 6 wt %; Bi₂O₃ isprovided in a range of 7 to 12 wt %; and CeO₂ is provided in a range of1 to 3 wt %.
 5. The composition of claim 4, wherein: the SiO₂ isprovided in a range of 37 to 41 wt %; the B₂O₃ is provided in a range of8 to 11 wt %; Na₂O is provided in a range of 6 to 13 wt %; K₂O isprovided in a range of 0 to 2.5 wt %; Li₂O is provided in a range of 0to 1.5 wt %; NaF is provided in a range of 1.4 to 2.9 wt %; ZnO isprovided in a range of 4 to 9 wt %; TiO₂ is provided in a range of 9 to12 wt %; MoO₃ is provided in a range of 4.5 to 5.5 wt %; Bi₂O₃ isprovided in a range of 8 to 11 wt %; and CeO₂ is provided in a range of1 to 2 wt %.
 6. The composition of claim 5, wherein at least one of:SiO₂ is provided in a range of 37.2 to 40.8 wt %; B₂O₃ is provided in arange of 8.3 to 10.5 wt %; Na₂O is provided in a range of 10.5 to 12.6wt %; K₂O is provided in a range of 1.1 to 2.2 wt %; Li₂O is provided ina range of 0 to 1.1 wt %; NaF is provided in a range of 1.5 to 2.8 wt %;ZnO is provided in a range of 4.5 to 8.8 wt %; TiO₂ is provided in arange of 9.3 to 11.7 wt %; MoO₃ is provided in a range of 4.7 to 5.1 wt%; Bi₂O₃ is provided in a range of 8.5 to 10.5 wt %; and CeO₂ isprovided in a range of 1.2 to 1.5 wt %.
 7. The composition of claim 6,wherein at least one of: SiO₂ is provided in a range of 37.30 to 40.70wt %; B₂O₃ is provided in a range of 8.39 to 10.30 wt %; Na₂O isprovided in a range of 10.96 to 12.46 wt %; K₂O is provided in a rangeof 1.12 to 2.11 wt %; Li₂O is provided in a range of 0 to 1.00 wt %; NaFis provided in a range of 1.63 to 2.74 wt %; ZnO is provided in a rangeof 4.65 to 8.51 wt %; TiO₂ is provided in a range of 9.50 to 11.60 wt %;MoO₃ is provided in a range of 4.81 to 5.01 wt %; Bi₂O₃ is provided in arange of 8.93 to 10.20 wt %; and CeO₂ is provided in a range of 1.32 to1.38 wt %.
 8. The composition of claim 1, wherein the total content ofNa₂O, K₂O, and Li₂O is provided in a range of 12 to 16 wt %.
 9. Thecomposition of claim 1, wherein at least one of: the total content ofNa₂O, K₂O, and Li₂O is provided in a range of 13.5 to 15.0%.
 10. Acoating layer on a substrate, the coating layer being made from thecomposition of claim
 1. 11. A cooking appliance having at least onesurface including the coating layer of claim 10 on a substrate.
 12. Amethod for preparing the composition of enamel of claim 1, the methodcomprising: providing a material of the composition for enamel, meltingthe material, and quenching the melted material.
 13. The method of claim12, wherein the material of the composition comprises 5 wt % or more ofNa₂O.
 14. The method of claim 12, wherein a total content of TiO₂, MoO₃,Bi₂O₃, CeO₂, and at least one of MnO₂, Fe₂O₃, or Co₃O₄ is 40 wt % orless.
 15. A composition for enamel prepared using the method of claim12.
 16. A coating layer made from the composition of claim
 15. 17. Acooking appliance including the coating layer of claim
 16. 18. A cookingappliance, comprising: a cavity having a cooking space therein; a doorto open or close the cooking space; at least one heat source configuredto provide heat in the cooking space; and a coating layer formed bycoating the composition of claim 1 on at least one of an inner surfaceof the cavity, an inner surface of the door, or an inner surface of adoor glass of the door.
 19. A cooking appliance, comprising: a glassplate; at least one heat source provided below the glass plate andconfigured to provide heat; and a coating layer formed by coating thecomposition of claim 1 on an upper surface of the glass plate.